Soil Amendment Calculator

Calculate how much lime, sulfur, gypsum, or compost to add to your soil. Enter area and application rate for bags and volume needed.

πŸ§ͺ Soil Amendment Calculator

Results

Area100.00 sq ft
Total Amount5.0 lbs
40 lb Bags1 bags
50 lb Bags1 bags

πŸ’‘ How to Calculate Soil Amendments

Soil amendments are applied at specific rates per 100 square feet, depending on the material and your soil test results. Agricultural lime is applied at 3–8 lbs per 100 sq ft, elemental sulfur at 0.5–2 lbs, and gypsum at 3–5 lbs. Compost amendments are measured in cubic feet.

Always start with a soil test to determine your soil's current pH and nutrient levels. Lime raises pH (makes soil less acidic), sulfur lowers pH (makes soil more acidic), gypsum improves clay soil structure without changing pH, and compost improves overall soil health and water retention.

A 10Γ—10 ft garden bed needing lime at 5 lbs per 100 sq ft: area = 100 sq ft, total lime = 5 lbs. For a 50Γ—50 ft lawn at the same rate: 2,500 sq ft Γ— 5/100 = 125 lbs = about 3 bags of 40 lb lime.

Soil Amendment Calculator FAQ